HIGH-PERFORMANCE AEROGEL DENO(X) CATALYST - CATALYTIC BEHAVIOR AND KINETIC MODELING

The kinetics and the parametric sensitivity of the selective catalytic reduction of NO by NH3 were investigated for a high surface area vana dia-titania aerogel. The catalyst showed high activity at low temperat ures and the selectivity to N-2 was higher than 99% for all experiment al conditions investigated. The addition of up to 2% H2O to the dry fe ed notably reduced the rate of NO conversion. The effect leveled off f or higher H2O concentrations. In the absence of O-2 in the feed the ac tivity collapsed, independently whether water was present or not. Smal l amounts of oxygen resulted in a sharp increase of the reaction rate, but for oxygen concentrations exceeding 4%, the increase diminished. A high tolerance with respect to sulfur dioxide was observed. The esti mated activation energy amounted to 60 +/- 1 kJ/mol. The microkinetic analysis resulted in a model based on an Eley-Rideal mechanism which d escribes the kinetic behavior over a wide experimental range.